Mathematics
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OpenStudy (lukecrayonz):
@amistre64 Fourth root of 625i, use the following to complete:
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OpenStudy (anonymous):
5 cos(pi/8)+5 i sin(pi/8)
OpenStudy (lukecrayonz):
..How
OpenStudy (lukecrayonz):
So how did you get theta?
OpenStudy (anonymous):
do you know the position of 625i in the complex plane ?
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OpenStudy (lukecrayonz):
Nope.
OpenStudy (lukecrayonz):
|dw:1330663917696:dw|
OpenStudy (anonymous):
it is on the y axis ( imaginary axis ) so the angle is pi/2
OpenStudy (lukecrayonz):
Since its on the imaginary axis?
OpenStudy (anonymous):
yep
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OpenStudy (lukecrayonz):
Alright so that makes sense :D
OpenStudy (anonymous):
cool
OpenStudy (lukecrayonz):
so for k, is it just n-1? Or what?
OpenStudy (lukecrayonz):
@amistre64
OpenStudy (amistre64):
for k?
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OpenStudy (lukecrayonz):
yes
OpenStudy (amistre64):
4th root is k=0,1,2,3; so 4 solutions using those values each time
OpenStudy (amistre64):
Fourth root of: 0+625i
t = pi/2 (90 degrees)
OpenStudy (lukecrayonz):
So if it was 7th root, k=0,1,2,3,4,5,6?
OpenStudy (amistre64):
yes
\[\frac{\frac{pi}{2}+2pi(k)}{4}=\frac{\frac{pi+4pi(k)}{2}}{4}=\frac{pi+4pi(k)}{8}\]
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OpenStudy (lukecrayonz):
Why is it pi+4pi(k)/2? Where did the dividing by two come into play?
OpenStudy (anonymous):
common denominator
OpenStudy (amistre64):
just simplifying it up by addinging fractions